dell xps one 2010

I am having video problems with my xps one 2010. Recently I noticed the fans were running at full speed then the video started flickering and went blank. Upon pushing the monitor on and off button, I can get the screen to come on for a few seconds and then it flickers and goes black. I can repeadedly turn the monitor on for a few seconds. When I boot I noticed the beeps changed to 3 quick beeps then 1 lower tone after a second then 1 higher tone after a second. This is consistent every time I boot. The computer boots up ok and will go into windows normally. It will also shut down normally.

I have reseated the memory and video card, did not notice an unusual amount of dust but cleaned out what was there. I do not use the original keyboard or mouse but I have been using a usb keyboard and mouse from dell for a long time. Computer was purchased in 12/2007. No warranty, fixing myself. Still running Vista Home.

I am trying to determine if this is a video card problem, power problem or LCD screen problem.

Any help would be appreciated.